The present invention relates generally to heat radiating systems for orbiting spacecraft or the like, and more particularly to a heat exchange radiator for absorbing and surviving a laser strike.
In the operation of spacecraft in earth orbit, high peak power generation furing certain portions of the duty cycle ordinarily require that a radiator system for rejecting waste heat generated aboard the spacecraft be sized to accommodate large heat loads. However, survival of the radiator system is usually critical to the continued successful operation of systems aboard the spacecraft and large overall physical size of the radiator system make it vulnerable to both natural and military threats. Conventional heat radiators generally comprise two-phase (liquid/vapor), pure substance, closed systems having large radiating surfaces which are especially susceptible to damage by invasive laser radiation. A laser beam directed onto the liquid tube or heat pipe fin radiating surfaces of a conventional radiator system may cause overpressure and overheating within the system, which would result in destruction of onboard operating systems whose continued functioning requires efficient heat rejection.
The invention described herein solves or reduces in critical importance problems with conventional heat radiators for spacecraft by providing a two-phase (liquid/vapor) heat exchange radiator system having substantial resistance to damage by invasive laser irradiation. The radiator system of the invention comprises a pair of heat pipes for conducting heat from a system aboard a spacecraft, two thin heat conducting wall members bonded to the heat pipes, the inner condensation surfaces of the wall members and the heat pipes defining a vapor chamber and the outer surfaces of the wall members defining heat radiating surfaces, a rewet artery of rolled or other suitably configured wicking material disposed within the vapor chamber between the heat pipes and extending substantially lengthwise of the vapor chamber, a pressure relief valve on the vapor chamber for venting vapor overpressure, and a source of expendable heat exchange medium operatively connected to the rewet artery for maintaining a liquid inventory on the condensation surfaces and for replacing vented vaporous heat exchange medium. The condensation surfaces have capillary grooves to maintain a liquid film inventory near the radiating surface and to provide high heat flux tolerance against failure of the wall members. The vapor chamber may comprise a compartmentalized structure for enhanced survivability of the overall system, each vapor chamber compartment including a relief valve.
It is therefore a principal object of the invention to provide an improved heat radiator system for spacecraft or the like.
It is another object of the invention to provide a heat radiator system having enhanced resistance to damage by invasive laser radiation.
It is a further object of the invention to provide a ventable waste heat radiator system for spacecraft.
These and other objects of the invention will become apparent as the detailed description of representative embodiments proceeds.